Nutrient knowledge

Scientists and researchers at two USDA Agricultural Research Services (ARS)are examining elements of nature that may soon help you increase yields -without having to pay a price.

Gluing carbon. In our July/August 1999 issue, page 42, we told you aboutcarbon, the hidden "crop." Now researchers at the ARS in Beltsville, MD,are learning how to increase the levels of this soil- and plant-buildingcommodity.

Soil scientist Sara F. Wright discovered a protein molecule named glomalinthat is produced by fungi that grows on most plant roots. The fungi feed oncarbon taken in by plant roots. The more the fungi eat, the more glomalinthey produce.

Glomalin acts like glue to improve soil stability by "gluing" soil intoclumps. Good soil clumping allows air and water to pass through the soilmore easily, boosts carbon levels and recycles nutrients to the plants.

Wright explains that, to obtain the most beneficial recycling of carbon andother naturally occurring nutrients, farmers should keep the ground coveredwith crops during the growing season for as long as possible and use atillage practice that offers minimal ground disturbance.

Moving right along. Plant physiologist, Daniel R. Bush, at the ARS inUrbana, IL, understands what nutrients plants need for growth. Now he'strying to figure out exactly how it allocates these nutrients to differenttissues of the plant.

"During photosynthesis, the main product the plant makes is sucrose," Bushsays. "Photosynthesis transforms light energy into a biochemical form thatis used to transform atmospheric CO2 into sucrose."

It's how the plant regulates where it allocates sucrose between competingtissue that intrigues Bush. "We have recently discovered a regulatorysystem that seems to control the sucrose transport protein and, ultimately,sugar availability," he explains.

The sucrose produced in photosynthesis comprises 90 percent of what is eventuallydistributed to the seed; 10 percent is amino acids used for proteins. "If we canlearn how the plant regulates the allocation of sucrose and amino acids, wecan learn how to manipulate the process," Bush says. "For instance we couldredirect the sugar to put more carbon into harvested tissue to increaseyields, or manipulate the amino acid content to add nutritional value tothe crop."